1. Field of the Invention
This invention relates to a mounting plate for a motor and, more particularly, to a mounting plate with an elastomeric gasket to isolate vibration of a blower motor from the motor support housing.
2. Description of the Related Art
Motors which provide a force of rotation to a drive shaft generate a certain amount of vibration as a result of the rotation of the drive shaft. The level of vibration, especially during starting and stopping, increases for electric motors in light of the combined vibration caused by the rotating armature and the rotating drive shaft.
It is desireable in many applications of motors having rotating drive shafts to dampen or isolate the vibration generated by the motor from the member supporting the motor. For example, passenger automobiles typically mount an electric blower motor in the passenger compartment of the automobile to circulate heated air for the heater and cool air for the air conditioning system. The motor has rotating armatures which provide the force of rotation for a drive shaft to which a fan is mounted for circulating the temperature controlled air. Because the motor is mounted in the passenger compartment, it is desireable to isolate the vibration generated by the motor from the member which supports the motor.
Several vibration isolating mounts and grommets are known which dampen vibration between two members. For example, one known motor dampening structure comprises a motor mounting plate having a central opening formed therein for receiving the motor drive shaft, fasteners to mount the motor to the plate and a plurality of U-shaped slots formed on the perimeter of the plate and adapted to receive elastomeric grommets. The grommets receive fasteners which mount the motor and mounting plate to a support member and dampen vibration generated by the motor.
Other examples of isolating mounting assemblies are seen in U.S. Pat. No. 5,131,619 issued Jul. 21, 1992 to Daugherty et al.; U.S. Pat. No. 4,522,378 issued Jun. 11, 1985 to Nelson; U.S. Pat. No. 4,520,987 issued Jun. 4, 1985 to Eguchi et al.; U.S. Pat. No. 4,306,708 issued Dec. 22, 1981 to Gassaway et al.; and U.S. Pat. No. 1,445,617 issued Feb. 13, 1923 to Jehu. Each of these prior art references suffer from the deficiency of adequately and effectively isolating the rotational force generated by the motor from the supporting member, especially during the starting and stopping of the motor.